JP3053264B2 - Decorative board having core sheet impregnated with vinyl ester resin - Google Patents

Abstract

A heat and pressure consolidated decorative laminate is disclosed having at least one core sheet which is impregnated with a vinyl ester resin. The resin is preferably derived from an epoxide terminated resin and an ethylenically unsaturated carboxylic acid. A particularly preferred epoxide terminated resin is the reaction product of bisphenol A and epichlorohydrin. Particularly preferred as the ethylenically unsaturated carboxylic acid are acrylic and methacrylic acid. The color of the core sheet(s) of decorative laminates embodying the invention is relatively light and thus can match the color of the face of optional back layers of the laminate where these, as is usual, are of a relatively light color. The laminates exhibit high heat resistance, flexibility, and good resistance to cracking and tearing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a heat and pressure bonded veneer having at least one core sheet impregnated with a vinyl ester resin. Preferably, the vinyl ester resin is derived from an epoxide terminated resin and an ethylenically unsaturated carboxylic acid.

[0002]

2. Description of the Related Art
The heat and pressure consolidated veneer was prepared from a core material comprising a plurality of phenolic resin impregnated kraft paper sheets, a melamine-formaldehyde resin impregnated face sheet and optionally a melamine resin impregnated overlay sheet. Such high pressure laminates were used worldwide as structural materials for wall panels and counter decks.

[0003] Decorative boards having a core sheet impregnated with melamine-formaldehyde and polyester have recently been reported. Such laminates offer several distinct advantages over laminates in which phenolic core materials are used. Most notably, the color of the core of the laminate matches the color of the faceplate or decorative sheet. As a result, the dark edge lines that are observed when a normal laminate is cut are eliminated.

For example, US Pat. No. 4,448,849 discloses hydroxyl for impregnating a core sheet and / or decorative sheet and / or overlay sheet to obtain a laminate having a solid color that edge-matches the color of the core surface. Melamine-formaldehyde resins containing melamine are disclosed. Further, U.S. Pat.
No. 968 discloses a laminate in which a core sheet is impregnated with a polyester containing a reaction product of a polyhydric alcohol, a saturated dicarboxylic acid and an unsaturated dicarboxylic acid. The polyester impregnated core sheet offers different advantages over laminates comprising a core sheet impregnated with melamine formaldehyde. In addition to being tear resistant, laminates comprising a polyester impregnated core sheet are characterized by greater flexibility, machinability, and punchability than laminates comprising a melamine formaldehyde impregnated core sheet. . In addition, laminates containing the polyester impregnated core sheet are less crazing resistant than laminates containing melamine-formaldehyde, as revealed by crack tests. Unfortunately, laminates comprising polyester cannot exhibit the high levels of heat resistance exhibited by laminates comprising melamine formaldehyde impregnated core sheets.

[0005]

SUMMARY OF THE INVENTION The present invention provides a high pressure veneer exhibiting increased heat resistance and tear resistance over laminates containing prior art polyester impregnated cores. In addition, the laminates of the present invention exhibit the very favorable flexibility, machinability, punchability and low cracking properties of laminates containing polyester. As with the prior art laminates containing impregnated melamine formaldehyde and polyester, the color of the laminate of the present invention matches the color of its faceplate or decorative sheet.

In particular, the present invention comprises a laminate comprising at least one core sheet impregnated with a core sheet treatment composition comprising a vinyl ester resin and an ethylenically unsaturated carboxylic acid. A catalyst for further curing and heat curing the resin component in the core sheet is further included together with the organic solvent. The invention further includes a laminate adjacent to the core sheet that includes a face sheet impregnated with a thermosetting melamine / formaldehyde reaction product. A backsheet impregnated with the melamine / formaldehyde reaction product may be further adjacent to the core sheet. The faceplate, one or more core sheets, and optional backsheet are consolidated by heat and pressure. The use of a vinyl ester resin in the core sheet treatment composition imparts greater flexibility and increased heat resistance to the consolidated laminate, further rendering it less susceptible to cracking and tearing. The laminates of the present invention are easily processed and are further characterized by one or more core sheet colors that match the colors of the face sheet and any backsheet.

In particular, the present invention comprises (a) a face plate impregnated with a thermoset melamine / formaldehyde reaction product; (b) a liquid thermoset epoxy vinyl ester resin and an ethylenically unsaturated crosslinkable monomer. At least two colored core sheets each impregnated with a core sheet treatment composition; and (c) a heat and pressure consolidated laminate comprising a backsheet impregnated with an optional thermosetting melamine / formaldehyde reaction product. I will provide a. The resulting consolidated laminate exhibits improved flexibility as revealed by winding tests performed at ambient or room temperature. In this test, the resulting laminate was compared to a currently commercially available laminate containing a core sheet impregnated with the melamine / formaldehyde reaction product, which wraps around a 5-6 inch (13-15 cm) radius. Wrap with a radius of 2-3 inches (5-8 cm). In addition, the united laminates show improved heat resistance, as well as NEMA radiant heat test LD3.7, NEMA blister resistance test
It is less susceptible to cracking and tearing than prior art laminates as revealed by LD3.15 and crack resistance tests.

In general, according to the present invention, the core sheet is made by impregnating a cellulose paper colored to match the color of the face sheet, and the face sheet and the back sheet are optionally pigmented or printed, patterned or designed. It is produced by impregnating an α-cellulose paper containing Are typically used in the basis weight of the paper core sheet 3000 ft2 about 60 to about 160 pounds per ream of (279m ²⁾ (about 27 to about 73kg), whereas, as used in the surface layer α Cellulose Seats are typically 300 square feet (27.9 m ² )
Reaches a basis weight of about 40 to about 120 pounds (about 18 to about 54 kg) per run. The core sheet may include any of several impregnated grades of paper, such as alpha cellulose paper, bleached kraft paper or cotton linter paper, which may be colored to better match the decorative sheet or face sheet.

The vinyl ester resin in the core sheet treatment composition does not affect the color of the colored core sheet. Also, the resin is color stable for a fairly long period of time and exhibits excellent resistance to acids, alkalis and oxidizing chemicals. The vinyl ester resin in the core sheet treatment composition further imparts increased flexibility and abrasion resistance to the laminate,
It is characterized by terminal ethylenic unsaturation and is substantially free of epoxide groups. Preferred vinyl esters are 180 ^° F. (82
About 10 to about 13 minutes at 77 ^° F (25 ° C)
And a Brookfield viscosity of about 400 to about 500 cps at 60 rpm at 60 rpm. It is preferably derived from the reaction of an epoxide-terminated resin with an organic carboxylic acid having α, β ethylenic unsaturation. The ethylenically unsaturated end groups are reactive with each other and with the ethylenically unsaturated crosslinkable monomer during curing of the resin. The epoxy equivalent of the epoxy vinyl ester resin is generally about 7,000 to about 20,000, and more preferably about 9,000
0 to about 10,000.

The epoxide resin used as the starting resin of the present invention is preferably a diglycidyl ether epoxy resin of the type derived from a bisphenol compound such as bisphenol-A and a halo-epoxy-substituted alkane such as epichlorohydrin. . Other epoxy resin raw materials that can be used include not only epoxidized phenol formaldehyde novolak resins, but also epoxide resins derived from polyhydric alcohols such as alkanediols and alkanetriols.

Particularly desirable epoxide resin raw materials are diepoxide resins derived from bisphenol-A and epichlorohydrin and having the general formula (n is an integer from 0 to 5). Desirably, such resins exhibit an epoxide equivalent weight in the range of about 150 to about 1,000. An epoxide equivalent of about 192 is preferred. Such an epoxy vinyl ester resin can be prepared by reacting an unsaturated carboxylic acid with a condensation product of bisphenol A and epichlorohydrin. The reaction of at least stoichiometric amounts of unsaturated organic acids with polyepoxide resins via their epoxy groups is known in the art. Preferred unsaturated carboxylic acids are 3-4
Unsaturated carboxylic acids containing two carbon atoms, acrylic acid and methacrylic acid are most preferred. Methacrylic acid is particularly preferred.

A particularly preferred vinyl ester resin is a vinyl ester resin represented by the following formula.

[0013]

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The organic carboxylic acid having ethylenic unsaturation for reacting the epoxide-terminated resin is preferably monobasic and may be selected from acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, and cinnamic acid. Not only may it be selected from higher alkylated acrylic acids such as ethyl, propyl and butyl-substituted acrylic acids. Suitable dicarboxylic acids are represented by maleic acid and fumaric acid. It is also possible to use half esters produced by the esterification of one mole of a hydroxy compound (for example, an alcohol) and one mole of an acid anhydride of an ethylenically unsaturated dicarboxylic acid (for example, maleic anhydride). Broadly speaking, the unsaturated organic acid should have at least one carboxyl group and, furthermore, a significant number of ethylenically unsaturated end groups, which in turn may be ethylenically unsaturated groups of the epoxide vinyl ester resin or preferably And may have an ethylenic unsaturation to give an epoxide-terminated resin, which may participate in an addition polymerization reaction with an ethylenically unsaturated crosslinking monomer).

[0015] The vinyl ester resin of the present invention may be cross-linked or cured by heat alone. It is preferred that a catalyst be used to cure the vinyl ester resin in preparing the core sheet impregnant. In particular, terminal carbon-carbon double bonds participate or cure in free radical polymerization when initiated by free radical catalysts such as organic peroxides and inorganic persulfates. Suitable peroxy catalysts are t-butyl perbenzoate, 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, and 1,1-di-tert-butylperoxy-3,3,5. -Including trimethylcyclohexane. The preferred catalyst is t-butyl perbenzoate.

[0016] The resin is preferably combined with an ethylenically unsaturated crosslinkable monomer, the resin being soluble in the monomer, which gives the resulting composition a low viscosity index. Suitable ethylenically unsaturated monomers are styrene, divinylbenzene, α-chlorostyrene, p-bromostyrene, t-butylstyrene, methyl methacrylate, and 2,3-dibromomethyl methacrylate, and the like. Low viscosity liquid monomers, especially styrene, are preferred. The amount of ethylenically unsaturated crosslinking monomer used is generally from about 20 to about 60% by weight of the core sheet treatment composition. Preferably, the amount of ethylenically unsaturated crosslinking monomer is from about 20 to about 60% by weight, preferably 30 to about 40% by weight, most preferably 36% by weight.

Preferably, a phenolic antioxidant is added to the core sheet treating composition. Antioxidants can be used to improve the shelf life of the resin system and prepreg by increasing the chance of termination of the vinyl ester resin. Phenolic antioxidants include various alkylated phenols, hindered phenols and phenol derivatives such as t-butylhydroquinone, butylated hydroxyanisole, polybutylated bisphenol A, butylated hydroxytoluene (BHT), alkylated hydroquinone, 2,6 -Di-tert-butyl-p-cresol, 2,5
-Di-tert-arylhydroquinone, octadecyl-3-
(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Irganox 1076), tetrakis [methylene 3- (3 ′, 5′-di-tert-butyl-
4'-hydroxyphenyl) propionate] methane (Irganox 1010), 2,2'ethylidenebis (4,6-di-tert-butylphenol) (Isonox 129), or 1,3,5-tris (4-tert- Butyl-3-hydroxy-2,6-dimethylbenzyl) -1,
3,5-triazine-2,4,6- (1H, 3H, 5
H) -trione (Cyanox 1790).
A preferred phenolic antioxidant is CaO-3, a product of Sherex Chemical Co.
butylated hydroxytoluene, commercially available from mpany). From about 0.001% to about 0.5% by weight of the core sheet treatment composition;
% By weight, preferably 0.01 to 0.10% by weight, most preferably
Antioxidant amounts in the range of 0.05% by weight are acceptable.

The vinyl ester treatment composition generally has a composition of about 20 to
100% by weight solids solution, the preferred amount of which is about
70-90% by weight, with the optimal amount being about 80 or 85% by weight. Generally, the core sheet treatment composition for impregnating each of the core layers comprises about 30 to 60 parts by weight of a vinyl ester resin, about 1 to about 70% by weight of an ethylenically unsaturated crosslinkable monomer, about 10 to 60 parts by weight. Parts of an organic solvent, and about 1 to 10% by weight of a free radical initiating catalyst. A particularly preferred composition comprises about 45 parts by weight of a vinyl ester resin, about 36.5 parts by weight of an ethylenically unsaturated crosslinkable monomer, most preferably styrene, about 2.
5 parts by weight of a free radical initiator, most preferably perbenzoic acid
-Butyl and about 16 parts by weight of organic solvent. Solvent 8
Preference is given to ketones containing up to carbon atoms.
Suitable solvents include methyl ethyl ketone, acetone and methyl isobutyl ketone. Acetone is most preferred.

The vinyl sheet impregnated core sheet further helps to provide the resulting consolidated laminate with significantly improved flexibility over prior art laminates. The laminates of the present invention are sufficiently flexible at ambient temperatures to wrap around 2-3 inches (5-8 cm) without breaking. This is in sharp contrast to prior art melamine / formaldehyde impregnated core sheet laminates, which only wrap with a radius of 5 to 6 inches (13 to 15 cm).

In impregnating the faceplate, a thermosetting melamine / formaldehyde reaction product is used, as is known in the art, which generally comprises from about 1.0 to 2.7 moles per mole of melamine, most preferably from about 1.0 to 2.7 moles. Preferably, it is a precondensate prepared from 1.5 to 2.25 mol of formaldehyde. If necessary, a small amount, for example, about 1 to 20% by weight of a modifier based on the weight of the reaction product can be used,
Such modifiers include dicyandiamide, ortho-p-toluenesulfonamide, sucrose, and glycols such as diethylene glycol.

In addition, the faceplate may be impregnated with a vinyl ester resin, preferably the same vinyl ester resin used to impregnate the core sheet. In preparing the multi-resin veneer of the present invention, the resin content of about 38 to 42% by weight is impregnated with the vinyl ester resin treatment composition, and is generally about 1.5 to 4% by weight, preferably about 2 to 3.5% by weight. about 5-9 sheets that have been dried to a volatile content of about ^{180 ~260 o F (82 ~127 ℃} ), preferably 7 or eight core sheets excellent results using was obtained.

The resulting laminate is generally about 0.05 to 0.07 inches (0.13 to 0.18 cm) thick, has not only improved flexibility but also a good color match and is resistant to chipping. In addition to having the desirable properties of formability, punchability, ease of handling, and ease of processing, it retains the usual expectations of strain resistance, scratch resistance, surface wear, and the like.

A preferred method of making the laminates of the present invention involves stacking the desired number and shape of impregnated sheets after at least partially drying and placing the stack between stainless steel press plates. Any textured sheet may be used and can be placed between the face sheets to give the face sheet a gloss and texture, and the textured sheet is removed after pressing. Then about 240 ^° F
(116 ° C) to 350 ^° F (177 ° C) at about 800 to 1400 psi (5
A pressure of 6.2-98.4 kg / cm ² ) is applied to the press plate for a period of 20 minutes to 90 minutes to effect hardening, thereby obtaining a high pressure decorative panel.

The following examples are intended to illustrate the invention, but do not limit it in any way.

[0025]

EXAMPLE 1 A roll of colored α-cellulose decorative paper, the paper having a basis weight of about 69 pounds (31 kg) per 3000 ft ² (279 m ² ), is treated with a melamine formaldehyde reaction product. Thus, a print or face plate was prepared. The melamine / formaldehyde reaction product is obtained by reacting 1 mole of melamine with 1.4 moles of formaldehyde and using 5 moles as a modifier.
Prepared by adding 1010% by weight of sucrose.

The paper web was carried on a reverse roll applicator for resin impregnation and passed through an air knife for resin metering to obtain 55% resin solids. The web was dried in a drying oven to 5% volatiles and the appropriate length of paper was cut from the web. Cores impregnated with vinyl esters by treating a roll of colored α-cellulose decorative paper having a basis weight of 90 pounds (41 kg) per 3000 ft ² (279 m ² ) in a core sheet treatment composition comprising a vinyl ester resin. A sheet was prepared. The vinyl ester resin is manufactured by Interplastics Corpora
is a bisphenol-epichlorohydrin epoxy system containing 45% by weight of styrene, commercially available as COREZYN VE8300 from E.C. The presence of styrene lowers the viscosity of the resin to 500 cps. The bisphenol-epichlorohydrin epoxy system is represented by the following formula:

[0027]

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The viscosity of the resin was reduced to 50 cps by diluting the resin with acetone. Addition of acetone further promotes penetration of the resin in the paper. Also, t-butyl perbenzoate, which is a high temperature curing catalyst, was added. In particular, the core sheet composition comprised the following components: Coregin VE8300 400 g t-butyl perbenzoate 12 g acetone 80 g CAO3 0.2 g The core sheet treatment composition was used to treat the colored core sheet to the following specified values.

RC35-40% Volatile content-3-5% Flow 0.5-2% A web of α-cellulose paper is placed in a dip pan containing vinyl ester resin and passed through a Meyer rod to give the desired resin. A content of 38% was obtained. The web was dried to 4% volatiles and cut into sheets comparable in length to printed sheets.

A solid color laminate was prepared by assembling the following constituent material sheets. One finish paper-aluminum foil release sheet One melamine-treated print sheet (face plate) Seven vinyl ester-treated core sheets One melamine-treated print sheet (back sheet) These sheets were subjected to 1200 psi (84 kg / cm ^2). 28) under pressure
Unite in a hydraulic press with a 1 hour full cure cycle at a peak temperature of 0 ^° F (138 ° C). After pressing, the finished paper was removed, the laminate was trimmed and sanded.

The resulting consolidated laminate has good flexibility, improved toughness, punchability and resistance to cracking when exposed to high and low temperatures, as shown by the following tests. showed that. The "polyester" used hereinafter for comparative purposes is a condensation product commercially known as MELCOR and was obtained from Pioneer Plastics.

Test Data Flexibility 3 "3" radiant heat of polyester product of the present invention , LD3.7 210 123 blister, LD 3.15 79 64 Crack No effect No effect Crack resistance was measured at 150 ^° F. (66 ° C.) The samples were exposed to a furnace temperature of 24 ° C. for 24 hours and a furnace temperature of 20 ^° F. (-7 ° C.) for 24 hours, and the product exposure to the temperature extreme was repeated for 5 days.

In addition, uniform coloring was evident throughout the laminate. In particular, the color of the core sheet matched the color of the top and back sheets. The laminate is flexible as revealed by a room temperature winding test, in which the laminate is wound with a radius of 2-3 inches (5-8 cm). The foregoing description of the invention is illustrative and illustrative. Those skilled in the art, after reading and understanding this disclosure, will recognize changes and modifications that can be made without departing from the scope and spirit of the invention described above and set forth in the claims. All such changes are intended to be within the scope of the claims.

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Claims (28)

(57) [Claims] Claims: 1. An article comprising at least one core sheet impregnated with at least a partially cured core sheet treatment composition comprising an epoxide-terminated resin and a vinyl ester resin derived from an ethylenically unsaturated organic carboxylic acid. A decorative plate characterized by that. 2. The decorative board according to claim 1, wherein each of the decorative boards includes at least two core sheets impregnated with the core sheet treating composition. 3. The decorative board according to claim 1, wherein the epoxide terminal resin is a diglycidyl ether epoxy resin. 4. The decorative panel according to claim 3, wherein the diglycidyl ether epoxy resin is derived from a bisphenol compound and a halo-epoxy-substituted alkane. 5. The decorative board according to claim 4, wherein the bisphenol compound is bisphenol A and the halo-epoxy-substituted alkane is epichlorohydrin. 6. The decorative board according to claim 3, wherein the acid is a monobasic acid selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, and cinnamic acid. 7. The method according to claim 6, wherein the monobasic acid is methacrylic acid.
A decorative plate according to claim 1 . 8. The decorative board according to claim 1, wherein the carboxylic acid is a diester of a dicarboxylic acid or a half ester produced by esterifying an acid anhydride of one mole of a hydroxy compound and one mole of an ethylenically unsaturated dicarboxylic acid. 9. The decorative board according to claim 8, wherein the dicarboxylic acid is selected from the group consisting of maleic acid and fumaric acid. 10. A vinyl ester resin having the formula: The decorative board according to claim 7, which is a resin represented by the following formula: 11. The core sheet treatment composition, wherein the styrene,
The composition of claim 1, further comprising an ethylenically unsaturated crosslinkable monomer selected from the group consisting of divinylbenzene, α-chlorostyrene, p-bromostyrene, t-butylstyrene, methyl methacrylate, and methyl 2,3-dibromomethacrylate. The decorative board according to claim 1. 12. The decorative board according to claim 11, wherein the ethylenically unsaturated crosslinking monomer is styrene. 13. The composition of claim 10, wherein the ethylenically unsaturated crosslinkable monomer comprises from about 20% to about 60% by weight of the core sheet treatment composition.
13. The decorative plate according to claim 12, which comprises: 14. The decorative sheet according to claim 11, wherein the core sheet treating composition further comprises a polymerization initiator that generates free radicals at an elevated temperature. 15. The decorative board according to claim 14, wherein the initiator is an organic peroxide or an inorganic persulfate. 16. The method according to claim 16, wherein the core sheet treating composition is about 10%.
12. The compound of claim 11, further comprising from about 60 parts by weight of an organic solvent .
Decorative board . 17. The method of claim 17, wherein the core sheet treatment composition comprises about 45
Parts by weight of the vinyl ester resin, about 36.5 parts by weight of styrene, about 2.5 parts by weight of t-butyl perbenzoate, and
17. The decorative board according to claim 16, comprising 16 parts by weight of acetone. 18. The decorative board according to claim 1, further comprising a face sheet impregnated with a thermosetting melamine / formaldehyde reaction product adjacent to the core sheet. 19. The melamine / formaldehyde reaction product in said face plate may be present in an amount of from about 1.0 to about 1.0 per mole of melamine.
19. The decorative board according to claim 18, which is a precondensate prepared from 2.7 mol of formaldehyde. 20. The decorative board according to claim 19, wherein the reaction product further comprises a sucrose modifier. 21. veneer according to claim 18 wherein the laminate further comprises a backing sheet which is impregnated with melamine / formaldehyde reaction product. 22. The cosmetic according to claim 18, wherein the carboxylic acid of the core sheet treating composition is a monobasic acid selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, and cinnamic acid. Board . 23. The monobasic acid is methacrylic acid.
23. The decorative plate according to 22. 24. The decorative board according to claim 22, wherein the epoxide-terminated resin of the core sheet treating composition is a diglycidyl ether epoxy resin. 25. A vinyl ester resin having the formula: 25. The decorative board according to claim 24, which is a resin represented by the following formula: 26. The core sheet treating composition, wherein the styrene,
The composition of claim 1, further comprising an ethylenically unsaturated crosslinkable monomer selected from the group consisting of divinylbenzene, α-chlorostyrene, p-bromostyrene, t-butylstyrene, methyl methacrylate, and methyl 2,3-dibromomethacrylate. 24. The decorative board according to 24. 27. The decorative board according to claim 26, wherein the ethylenically unsaturated crosslinkable monomer is styrene. 28. The ethylenically unsaturated crosslinking monomer comprises from about 20% to about 60% by weight of the core sheet treatment composition.
28. The decorative plate according to claim 27, comprising: